PTAB

IPR2014-00244

Fifth Third Bank v. Stambler Leon

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method for Securing Information Relevant to a Transaction
  • Brief Description: The ’302 patent discloses methods for authenticating parties and securing information in a transaction. The core of the invention involves "coding" information associated with a party or transaction to generate a "variable authentication number (VAN)," which is then used for verification.

3. Grounds for Unpatentability

Ground 1: Anticipation over Davies - Claims 7, 41-43, 45, and 48 are anticipated by Davies.

  • Prior Art Relied Upon: Davies (D. W. Davies et al., Security for Computer Networks, 1989).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Davies, a foundational text on computer and network security, taught every element of the challenged claims. For independent claim 7, which recites a method for coding information, Petitioner asserted that Davies’s description of public-key digital signatures meets the claim limitations. Specifically, Davies allegedly disclosed generating a signature by "coding" a message (first information) with a sender's private key (second information) and then "coding" the resulting signature with the receiver's public key (third information). For independent claim 41, which recites authenticating a fund transfer, Petitioner argued that Davies’s disclosure of electronic check systems met the limitations. Davies described a customer (first party) generating a digital signature (VAN) on payment information, which is then authenticated by a third-party bank before funds are transferred to a payee (second party).

Ground 2: Obviousness over Davies in view of Nechvatal - Claims 46 and 51-55 are obvious over Davies in view of Nechvatal.

  • Prior Art Relied Upon: Davies (Security for Computer Networks, 1989) and Nechvatal (James Nechvatal, Public-key Cryptography, NIST Special Publication 800-2, Apr. 1991).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon Davies by adding Nechvatal to teach limitations related to an "error detection code" (EDC). Claim 46, which depends from claim 41, requires that the VAN be generated using an EDC. Petitioner argued that while Davies taught generating a signature (VAN) from transaction data using a one-way hash function, Nechvatal explicitly taught that such hash functions "serve as cryptographic checksums (i.e., error-detecting codes)." Therefore, Nechvatal supplied the express teaching that the hash function used in Davies’s signature generation was an EDC.
    • Motivation to Combine: A POSITA would combine Davies and Nechvatal to improve the efficiency of the digital signature system taught in Davies. Nechvatal explained that using hash functions mitigates data expansion and reduces bandwidth requirements, providing a clear rationale for incorporating this well-understood technique into Davies’s electronic transaction framework.
    • Expectation of Success: The combination involved applying a known data-condensation technique (hashing as an EDC, per Nechvatal) to a known cryptographic process (digital signatures in Davies) to achieve a predictable improvement in efficiency. A POSITA would have had a high expectation of success.

Ground 3: Obviousness over Piosenka in view of Fischer - Claim 31 is obvious over Piosenka in view of Fischer.

  • Prior Art Relied Upon: Piosenka (Patent 4,993,068) and Fischer (Patent 4,868,877).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claim 31, a method for issuing a credential. Petitioner asserted Piosenka taught a method where a personal identification system (second party) issues a credential to a user (first party) after authenticating their background information. However, Petitioner argued Piosenka’s credential did not include information identifying the issuing system itself. Fischer allegedly cured this deficiency by teaching the creation of certificates that include information about the certifying authority (e.g., the authority’s identity and public key).
    • Motivation to Combine: A POSITA would combine Fischer with Piosenka to make the credentials issued by Piosenka’s system more versatile. Including the certifying authority's information, as taught by Fischer, would allow various validation systems to identify the credential's origin and use the correct public key for verification, a predictable and desirable improvement over a closed system.
    • Expectation of Success: Modifying Piosenka’s credential to include identifying information from Fischer’s certificate structure was a straightforward combination of known elements from the field of identity verification, leading to a high expectation of success.
  • Additional Grounds: Petitioner asserted additional obviousness challenges, including grounds that claims 47 and 56 are obvious over Davies, Fischer, and Piosenka; claim 8 is obvious over Davies and Hellman (Patent 4,200,770); and claims 33-34 are obvious over Fischer and Nechvatal.

4. Key Claim Construction Positions

  • "Coding": Petitioner proposed construing this term as "transforming information by applying a known algorithm." This construction was critical for asserting that standard cryptographic operations like encryption, decryption, and hashing, as disclosed in the prior art, met the "coding" limitation of the claims.
  • "Variable Authentication Number (VAN)": Petitioner proposed construing this term as "a variable number resulting from a coding operation that can be used in verifying the identity of a party or the integrity of information or both." This broad construction was key to arguing that a digital signature, as commonly understood and described in the prior art, qualified as the claimed VAN.
  • "Credential": Petitioner proposed construing this term as "a document or information obtained from a trusted source that is transferred or presented to establish the identity of a party." This allowed prior art disclosures of digital certificates containing public keys to be mapped to the "credential" limitation.

5. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 7, 8, 31, 33-34, 41-43, 45-48, and 51-56 as unpatentable.